I'm using a 10 year old computer right now. The original Mac Pro 1,1. It's just as fast as the Mac Pro we got at work that was purchased in 2013. Figure that one out.
The other thing that sucks about Apple products is even if you buy an iPhone 6 or iPhone 5s RIGHT NOW, it comes pre-loaded with the latest software whether you want it to or not. So you're not getting the OS that was optimized for that hardware unless you buy the hardware when that OS is the most current.
Also, once Apple stops signing an older OS, if you upgrade, there's no going back. So think about this for a second. Let's say I'm sitting here with iOS 8.3 and it works fine for me, however some of the iOS 9.2 features are tempting to me. I'll go on a forum and see how people are liking it. However, I have to sift through people arguing back and forth about how it lags and how it doesn't lag and it's all in the users head. Also, you have people saying stuff like "9.2 fixed almost all the lags for me and it's just as fast as 8.4.1".
So maybe after seeing some people praise the 9.2 update, I might be tempted to try it, however if I update, I can't go back. That's the part that sucks. I updated to 9.1 from 8.4.1 because A) The Music app sucked on 8.4.1 as it wasn't really designed to be a part of iOS 8 fully and B) because some people said it fixed the lagginess of 9.0 (in some ways it did and it was definitely better, but not completely fixed). Now, Apple has stopped signing 8.4.1 and now I just have to hope Apple will further optimize iOS 9 on my outdated iPhone 6, but they probably don't care about their older hardware because why would anyone buy a 6s if the 6 was just as fast?